ln 1980 we began a prospective study designed to examine the relationship between nutrition and health status in a group of 304 initially healthy individuals. These subjects were recruited in 1979 and were at least 60 years of age, in good health, and taking no prescription medication. Nutritional status was evaluated yearly using three day diet records and biochemical parameters. Health status as determined by a yearly history and physical exam and review of private physician and hospital records when appropriate. In addition, this elderly population was examined periodically for hearing deficits, major life events, cognitive and mental status, and immune status. One goal of this application is to obtain additional longitudinal information on age related changes of nutritional status as determined by yearly clinical, dietary, and biochemical measurements. Two new studies that utilize magnetic resonance imaging (MRl) are proposed that will assess critical outcome variables in this aging population. The first will investigate body composition and changes in fat and muscle mass distribution with aging. In this study, MRl will be used to measure the distribution of fat and muscle directly from three different cross-sectional scans. These data will be used to standardize common anthropometric measurements and to describe the rate of redistribution of fat and muscle in this aging population. The second proposed study will correlate the development of MRl abnormalities in diffuse white matter in the brain, with changes in cognitive status measured by standard neuropsychological exams. This study will continue to supply biological samples for a parallel study designed to analyze the vitamin D-endocrine system for age-related changes in vitamin D nutritional status, renal bioactivation of 25-hydroxy vitamin D, and renal responsiveness to parathyroid hormone.